Preservation of Salmon Eggs (not for consumption)

Product Development
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I was wondering if any of you could humor a question I have regarding the preservation of raw salmon eggs at room temperature.

I am interested in making Chinook Salmon eggs, or roe, shelf stable through pasteurization, vacuum sealed in mason jars at 70 degrees Celsius for 90 minutes. Any higher temperature or duration seems to have negative effect on color and consistency of the egg.

So far I have gotten them to maintain a shelf-life of nearly two weeks at room temperature. I would like to extend that to 1 year or greater.

I cannot change the consistency or color of the egg as they are used for fishing, not for human consumption. They can’t have their scent adulterated, either. Whatever additive I can add to the jar doesn’t have to be food safe but they can’t have any smells or flavors as the fish they’re being used for can smell parts per million.

The egg must come out of the sealed jar after, say 6 months, not dissimilar to the way they entered regarding scent, color, and consistency.

I can’t use alcohol because they change the scent and dehydrate the egg membrane. I can’t use iodine because it’s yellow and smells. I understand thay most food preservatives, such as potassium sorbate, is mostly effective against yeast, less so for bacteria. I can’t boil them because it changes the egg.

I’m not a food scientist (read:I’m not a scientist) and don’t know where to go from here. I’ve done extensive Googling and am getting nowhere.

I have considered dehydration but haven’t tried. I’m concerned the membrane will be damaged in the process. The issue with damaging the membrane is that they “milk” quickly. Meaning that they go from bright orange to white. Fresh eggs make it about 45 minutes to 1 hour. That’s the target. Freezing them damages the membrane from crystallization and they milk faster. Like milking after 10 to 20 minutes. They’re useless after being fully milked and have to be changed. I’ve found that if I freeze them in a cryogenic fashion and thaw them slowly in the fridge, they milk normally. However, I can’t recreate that on a large scale nor sell on bait store shelves whilst frozen. But it’s a cool discovery anyway.

So I went down the road of UVC exposure and was mere moments from buying the equipment to tumble jars of spawn (roe) under a light system when I came across the little cumbersome fact that the glass of the jars will absorb 100% of the UVC radiation and the eggs will never be exposed. So I quit there.

I’ve thought about tumbling them under UV light but I figure it would have to be in a clean environment otherwise they’ll just be contaminated via airborne pathogens on their way to their jars before sealing. I’m also not interested in making a laminar flow hood large enough to make the light machine and have enough space to jar them. It’s just not practical.

So this is when I turned to a chemical option. Where I also struck out.

I understand if you’re not interested in giving your two-cents but if you are… I’d really really appreciate it.

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Hi Lyndon, how about IQF (Individually Quick Freezing) using a fluidized bed? You’ll get a product like frozen peas that will pour out the package individually without sticking to one another. Since they are frozen very fast, the membrane may not be damaged. The process may be optimized for that. The user will store the product in the freezer and he is going to thaw it in the refrigerator hours before use.
Your product will not be shelf stable since it can not be stored at room temperature for an extended time. However it will have a long life when kept frozen at -18C.
I was thinking about sterilization by irradiation using gamma rays or UV. Sterilization needs high doses of energy be applied. Therefore both technologies may damage the sensitive flavor of the product.
I hope that helps :wink:

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Yeah, my immediate thought was irradiation, but you would need a facility close by.

If you have a process that works for everything except colour, you can add colourants. That’s easy.

You’ve got a high pH product, so that’s tricky.

I assume brining won’t work to preserve the eggs? You have looked at acidifying or alkalizing? Biocides? Lysozyme? Antibacterial peptides?

Have you tried higher temp, lower time, or switching from jars to retort pouches to get a better surface area to volume ratio so you get faster heat and cool?

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I really appreciate your input but they must be shelf stable for my purpose.

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I have researched Biocides but i dont know which have smells and tastes. Im assuming most. I dont know anything about Lysozymes so im researching now. Same with Antibacterial peptides. Thanks!!!

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Dear folk
Please share your raw salmon egg size (WxL) and weight, moisture as well as maintain egg for a shelf-life of nearly two weeks at room temperature.
you may also contact me personally on [email protected]
for extend shelf life1 year or greater

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In food preservation, “hurdle concept” is used to define a process where not one but many hurdles are used against microorganisms. In stead of applying one severe process (heat sterilization, drying, etc.), you have many small treatments coupled together. For example, you reduce the moisture a bit, use antimicrobial agents at a low concentration, apply modified atmosphere packaging, refrigerate the product and so on. However, it is not as straight forward as using one single treatment. It takes trial and error and challenge studies may be needed.
Please let us know if you find a satisfatory solution to your problem.

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